Of course it is not supported, I don't expect that to be fixed. I thought knowing that there is a problem with the current Chrome dev version would be a valuable info for the developers of the clipper extension for future versions.
Same here. OSX 10.7.3, Chrome 19.0.1061.1 dev, Evernote Web Clipper doesn't work (only shows an empty 1-line box when clicking on the extension icon). Uninstalling / Reinstalling the extension does not solve the problem.